Composite container having barrier property

ABSTRACT

A composite container having a barrier property and comprising a packaging material which comprises an inner surface layer, a barrier layer, and a base material layer wherein the barrier layer comprises one selected from nylon MXD 6 and a semi-aromatic polyamide resin, which is a copolymer comprising an aromatic polyamide forming component and an aliphatic polyamide forming component wherein the aromatic polyamide forming component comprises an aliphatic diamine and isophthalic acid and/or terephthalic acid, and the aliphatic polyamide forming component comprises a lactam or an aliphatic diamine, and an aliphatic dicarboxylic acid. The above packaging material may also comprise an inner surface layer having a barrier property and a base material layer wherein the inner surface layer having a barrier property comprises the above semi-aromatic polyamide resin. Such a composite container having a barrier property has both of a good barrier property and a sufficient strength, and is capable of being produced at a low cost without complicating the production process to be used therefor.

This is a divisional of application Ser. No. 07/791,080 filed on Nov.12, 1991 now U.S. Pat. No. 5,433,982.

BACKGROUND OF THE INVENTION

The present invention relates to a composite container having a barrierproperty, particularly to a composite container which has a good barrierproperty and a sufficient strength, and is capable of being produced ata low cost without complicating the production process to be usedtherefor.

Hitherto, when a composite container which is required to have a gasbarrier property is produced, there has generally been used a productionprocess wherein the packaging material for constituting such a containeris caused to have a laminate structure, and a layer of an aluminum foilis disposed or interposed in the laminate structure. In addition, such acontainer is generally disposable, i.e., is thrown away after a singleuse thereof.

However, it has recently been required that the resources (or naturalresources) are to be recycled. From such a viewpoint, there has beendemanded a container which is capable of being collected after the usethereof and being separated into the respective materials constitutingthe container so that the thus separated materials can be recycled orreused. However, in the case of the conventional container formed fromthe packaging material as described above using the aluminum foil, therehas been posed a problem such that the aluminum oil disposed orlaminated between the layers of resins or papers cannot be easilyseparated and collected.

In order to solve such a problem, there have been developed containersof various types which have a good barrier property without using ametal thin film such as an aluminum foil. For example, Japanese LaidOpen Patent Application (JP A, KOKAI) No. 22624/1988 discloses acontainer which is formed from a packaging material having a five layerstructure comprising a polyethylene (PE) resin layer/a paper layer/a PEresin layer/a nylon 6 layer/and a PE resin layer disposed from the innerside of the container; Japanese Laid Open Patent Application No.312143/1988 discloses a container which is formed from a packagingmaterial having a five layer structure comprising a polyethylene (PE)resin layer/a paper layer/a PE resin layer/an ethylene-vinylalcoholcopolymer (EVOH) layer/and a PE resin layer disposed from the inner sideof the container; Japanese Laid Open Patent Application No. 160551/1990discloses a container which is formed from a packaging material having asix layer structure comprising a polyethylene (PE) resin layer/a paperlayer/a PE resin layer/an EVOH layer/a nylon 6 layer/and a PE resinlayer disposed from the inner side of the container; etc.

However, among these conventional containers, the first container asdescribed above has a problem such that the Nylon 6 layer only providesan insufficient gas barrier property. Further, in the case of the secondcontainer as described above, the EVOH layer may provide a Good barrierproperty but it does not have a sufficient strength. In addition, whensuch a container is used as one for containing a soft drink, since theEVOH layer may take up water and the barrier property of the EVOH layermay extremely decrease when the EVOH layer contacts such a content, itis required to subject the end surface disposed inside of the containerto a treatment such as skiving so that the EVOH layer may be coveredwith another material. As a result, the second container has a problemsuch that it requires a complicated production process. Further, in thecase of the third container as described above, since the substratematerial layer is disposed outside the EVOH layer and the nylon 6 layer,the container can have both of an excellent barrier property and asufficient strength but it requires a higher production cost because ithas both of the EVOH layer and the nylon 6 layer.

On the other hand, in a case where a pouring member is mounted the abovecomposite container having a barrier property, it has been used a methodwherein a pouring member, e.g., comprising a polyolefin resin such aspolyethylene is inserted into an opening formed in the main body of thecomposite container so that it is penetrated from the inner side of themain body of the composite container, and a flange portion of thepouring member is fixed to the inner peripheral surface of the main bodyof the composite container.

In the case of the conventional composite container having such apouring member mounted thereto, when the polyolefin type resin layer isformed at the time of the production of the laminate sheet as a materialconstituting the container, or when the container is formed from thelaminate sheet, the polyolefin type resin is subjected to pyrolysis toproduce a volatile component such as aliphatic hydrocarbons. Therefore,such a container has a problem such that the volatile component maymigrate to the content such as an orange juice contained in thecontainer so that the taste of the content may be changed or an odor isimparted to the content; or the flavor or taste of the content isimpaired because the polyolefin type resin layer constituting the innerperipheral surface layer is liable to adsorb or transmit the flavorcomponent of the content such as the orange juice.

From such a viewpoint, there has been investigated or researched, as acomposite container which is excellent in a flavor component retainingproperty, a composite container wherein the inner layer comprises alayer of a semi-aromatic polyamide resin which is a copolymer comprisesan aromatic polyamide forming component comprising an aliphatic diamineand isophthalic acid and/or terephthalic acid; and an aliphaticpolyamide forming component comprising a lactam or an aliphatic diamineand an aliphatic dicarboxylic acid.

However, according to the present inventor's investigation, when apouring member comprising an integrally molded member comprising apolyolefin type resin such as polyethylene is intended to be applied ormounted to such a composite container having a flavor componentretaining property, a sufficient adhesion property between the containerand the pouring member has not been obtained.

SUMMARY OF THE INVENTION

An object of the present invention is, in view of the above problemsencountered in the prior art, to provide a composite container having abarrier property which has both of a good barrier property and asufficient strength, and is capable of being produced at a low costwithout complicating the production process to be used therefor.

Another object of the present invention is to provide a compositecontainer having a barrier property which is equipped with a pouringmember.

According to a first aspect of the present invention, there is provideda composite container having a barrier property and comprising apackaging material which comprises:

an inner surface layer comprising a polyolefin type resin,

a barrier layer, and

a base material layer wherein at least the outermost layer thereofcomprises an olefin type resin,

wherein the barrier layer comprises one selected from nylon MXD6 and asemi-aromatic polyamide resin, which is a copolymer comprising anaromatic polyamide forming component and an aliphatic polyamide formingcomponent wherein the aromatic polyamide forming component comprises analiphatic diamine and isophthalic acid and/or terephthalic acid, and thealiphatic polyamide forming component comprises a lactam or an aliphaticdiamine, and an aliphatic dicarboxylic acid.

According to the above first aspect of the present invention, theresultant container has both of a barrier property and a strength. Inaddition, since a reinforcing layer is not required to be disposedtherein, the production process for producing such a container can besimplified and the production cost can be reduced.

According to a second aspect of the present invention there is provideda composite container having a barrier property and comprising apackaging material which comprises:

an inner surface layer having a barrier property, and

a base material layer wherein at least the outermost layer thereofcomprises an olefin type resin,

wherein the inner layer having a barrier property comprises asemi-aromatic polyamide resin, which is a copolymer comprising anaromatic polyamide forming component and an aliphatic polyamide formingcomponent wherein the aromatic polyamide forming component comprises analiphatic diamine and isophthalic acid and/or terephthalic acid, and thealiphatic polyamide forming component comprises a lactam or an aliphaticdiamine, and an aliphatic dicarboxylic acid.

According to the above second aspect of the present invention, there maybe provided a composite container having a barrier property which hasnot only an excellent gas barrier property, an excellent flavor barrierproperty and a sufficient strength, but also has an excellentsuitability to a container for a drink, and is capable of being producedat a low cost by use of a simplified production process.

According to a third aspect of the present invention, there is provideda composite container having a barrier property and comprising acontainer main body having an opening and a pouring member which hasbeen inserted into the opening formed in the container main body fromthe inside of the container main body,

wherein the container main body comprises an inner surface layercomprising a semi-aromatic polyamide resin, which is a copolymercomprising an aromatic polyamide forming component and an aliphaticpolyamide forming component wherein the aromatic polyamide formingcomponent comprises an aliphatic diamine and isophthalic acid and/orterephthalic acid, and the aliphatic polyamide forming componentcomprises a lactam or an aliphatic diamine, and an aliphaticdicarboxylic acid; the pouring member comprises a pouring member formingmaterial comprising an adhesive polyolefin type resin, and has a flangeportion; and the flange portion is fixed to the inner surface layer ofthe container main body.

According to a fourth aspect of the present invention, there is provideda composite container having a barrier property and comprising acontainer main body having an opening and a pouring member which hasbeen inserted into the opening formed in the container main body fromthe inside of the container main body,

wherein the container main body comprises an inner surface layercomprising a semi-aromatic polyamide resin, which is a copolymercomprising an aromatic polyamide forming component and an aliphaticpolyamide forming component wherein the aromatic polyamide formingcomponent comprises an aliphatic diamine and isophthalic acid and/orterephthalic acid, and the aliphatic polyamide forming componentcomprises a lactam or an aliphatic diamine, and an aliphaticdicarboxylic acid; the pouring member comprises a pouring member formingmaterial comprising the semi-aromatic polyamide resin, and has a flangeportion; and the flange portion is fixed to the inner surface layer ofthe container main body.

According to a fifth aspect of the present invention, there is provideda composite container having a barrier property and comprising acontainer main body having an opening and a pouring member which hasbeen inserted into the opening formed in the container main body fromthe inside of the container main body,

wherein the container main body comprises an inner surface layercomprising a semi-aromatic polyamide resin, which is a copolymercomprising an aromatic polyamide forming component and an aliphaticpolyamide forming component wherein the aromatic polyamide formingcomponent comprises an aliphatic diamine and isophthalic acid and/orterephthalic acid, and the aliphatic polyamide forming componentcomprises a lactam or an aliphatic diamine, and an aliphaticdicarboxylic acid; the pouring member comprises a pouring member formingmaterial comprising a polyolefin type resin, and has a flange portion;and the flange portion is fixed to the inner surface layer of thecontainer main body by the medium of a laminating material comprising asemi-aromatic polyamide resin layer comprising the semi-aromaticpolyamide resin.

According to the above third, fourth and fifth aspects of the presentinvention, there may be provided a composite container equipped with apouring member which has not only an excellent gas barrier property, anexcellent flavor barrier property and a practical (or a practicallyacceptable) strength, but also has a good adhesion property between thepouring member and the main body of the container so that the pouringmember and the main body of the composite container cannot be easilyseparated or peeled from each other.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing a packaging material to beused for the composite container having a barrier property according tothe present invention.

FIG. 2 is a graph showing an oxygen permebility constant (orcoefficient) of each of nylon MXD6 and other resins.

FIGS. 3 and 4 are schematic sectional views each showing a packagingmaterial to be used for the composite container having a barrierproperty according to the present invention.

FIG. 5 is a schematic perspective view showing an embodiment of thecomposite container equipped with a pouring member according to thepresent invention.

FIG. 6 is a schematic sectional view showing a cross section of thecomposite container equipped with a pouring member taken along the lineVI--VI shown in FIG. 5.

FIG. 7 is a schematic perspective view showing an embodiment of thecomposite container equipped with a pouring member according to thepresent invention.

FIG. 8 is a schematic sectional view showing a cross section of thecomposite container equipped with a pouring member taken along the lineVIII--VIII shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, the present invention will be described in detail withreference to preferred embodiments of the present invention.

FIG. 1 is a schematic sectional view showing a packaging material forforming the composite container having a barrier property according toan embodiment of the present invention.

In FIG. 1, a packaging material 1 comprises a laminate comprising aninner layer 2 for providing an innermost surface of the container, abarrier layer 3 disposed outside the inner layer 2 by the medium of anadhesive layer 8a, and a base material layer 4 disposed outside thebarrier layer 3 by the medium of an adhesive layer 8b.

The inner layer 2 may comprise a polyolefin type resin such as lowdensity polyethylene, medium density polyethylene, ethylene-α olefincopolymer, and ethylenevinylacetate copolymer. The inner layer 2 is alayer for heat fusing the inner layers 2 with each other, or heat fusingthe inner layer 2 with an outermost layer of the base material layer 4at the time of the formation of the composite container. The adhesivelayers 8a and 8b to be disposed between the inner layer 2 and thebarrier layer 3 and between the barrier layer 3 and the base materiallayer 4 may predominantly comprise an adhesive polyolefin type resin (ora polyolefin type resin having an adhesive property).

As such an adhesive polyolefin type resin to be used for the adhesivelayers 8a and 8b, there may be used a poly α-olefin such aspolyethylene, ethylene-α olefin copolymer, polypropylene, polybutene,and polyisobutylene; a polydiolefin such as polybutadiene, andpolyisoprene; or a copolymer etc., comprising one or at least twospecies of ethylene type unsaturated monomers. Such an ethylene typeunsaturated monomer may singly have a carbonyl group based on carboxylicacid, carboxylic acid salt, carboxylic acid anhydride, carboxylic acidester, carboxylic acid amide, carboxylic acid imide, aldehyde, ketone,etc.; or may have such a carbonyl group in combination with cyano group,hydroxy group, ether group or oxirane ring, etc.

Specific examples of the ethylene type unsaturated monomer used for sucha purpose may include:

(A) ethylene type unsaturated carboxylic acid: acrylic acid, mathacrylicacid, maleic acid, fumaric acid, crotonic acid, itaconic acid,citraconic acid, 5-norbornen-2,3-dicarboxylic acid, etc.,

(B) ethylene type unsaturated carboxylic acid anhydride: maleic acidanhydride, citraconic acid anhydride, 5-norbornen-2,3-dicarboxylic acidanhydride, tetrahydrophthalic acid anhydride, etc.,

(C) ethylene type unsaturated ester: ethyl acrylate, methylmethacrylate, 2-ethylhexyl acrylate, monoethyl or diethyl maleate,vinylacetate, vinyl propionate, γ-hydroxy propyl methacrylate, β-hydroxyethylacrylate, glycidyl acrylate, glycidyl methacrylate,β-N-ethylaminoethyl acrylate, etc.,

(D) ethylene type unsaturated amide or imide: acrylamide,methacrylamide, maleinimide, etc.,

(E) ethylene type unsaturated aldehyde or ketone: acrolein,methacrolein, vinyl methylketone, vinyl butyl ketone, etc.

It is also possible to incorporate a polyolefin resin, particularlypolyethylene, into the adhesive layer 8a comprising such an adhesivepolyolefin type resin. In such a case, the amount of the above adhesivepolyolefin type resin contained in the adhesive layer 8a may preferablybe 40 wt. % or larger. When the amount of the adhesive polyolefin typeresin layer is smaller than 40 wt. %, the adhesive property of theadhesive layer 8a to the barrier layer 3 may undesirably be decreased.Such an adhesive layer 8a may preferably have a thickness of about 3 to30 μm. In addition, the inner layer 2 may preferably have a thickness of5 to 100 μm.

The barrier layer 3 may generally comprise a semi-aromatic polyamideresin comprising an aromatic polyamide forming component comprising analiphatic diamine and isophthalic acid and/or terephthalic acid; and analiphatic polyamide forming component comprising a lactam or analiphatic diamine, and an aliphatic dicarboxylic acid; or Nylon MXD6comprising a aromatic polyamide resin produced by a polycondensationreaction between metaxylenediamine and adipic acid.

More specifically the above, semi-aromatic polyamide resin may generallycomprise a copolymer comprising 100 to 80 wt. % of an aromatic polyamideforming component comprising an aliphatic diamine and isophthalic acidand/or terephthalic acid; and 0 to 40 of an aliphatic polyamide formingcomponent comprising a lactam or an aliphatic diamine and an aliphaticdicarboxylic acid. Such a semi-aromatic polyamide resin has a lowercrystallinity as compared with that of an ordinary aliphatic polyamideresin, and shows a characteristic of an amorphous resin. Thesemi-aromatic polyamide resin may be caused to directly contact a liquidcontent such as a soft drink to be contained in the container without adecrease of the barrier property, unlike the EVOH resin as describedabove, and therefore the treatment such as skiving to be used for theend surface of the packaging material is not required so that theproduction process for the container may be simplified. In addition, thesemi-aromatic polyamide resin has a strength which is comparable to thatof the Nylon 6 resin, and therefore the provision of a reinforcing layeris not required so that the production cost for the container can bereduced.

On the other hand, the Nylon MXD6 as described above is a crystallinethermoplastic polymer which is capable of being produced by apolycondensation reaction between metaxylenediamine (MXDA) and adipicacid, and is a polyamide resin represented by the following chemicalformula. ##STR1##

In the above formula, n denotes an integer satisfying a relationship of10<n<10,000.

The Nylon MXD6 has a good barrier property on the basis of the aromaticring contained in the main chain thereof.

FIG. 2 is a graph showing an oxygen permeability constant (orcoefficient) of each of Nylon MXD6 and other resins. As apparent fromFIG. 2, the Nylon MXD6 has a lower oxygen permeability constant under arelative humidity of 100% which is important for a container forcontaining a liquid content such as a soft drink, as compared with notonly the conventional Nylon 6 but also the ethylene vinyl alcoholcopolymer (EVOH).

Therefore, the treatment such as skiving to be used for the end surfaceof the packaging material comprising EVOH resin is not required so thatthe production process for the container may be simplified. In addition,the Nylon MXD6 has a strength which is comparable to that of the Nylon 6resin, and therefore the provision of a reinforcing layer is notrequired so that the production cost for the container can be reduced.

The semi-aromatic polyamide resin or the Nylon MXD6 may preferably becontained in the barrier layer 3 in an amount of about 20 to 200 wt. %.When the amount of the semi-aromatic polyamide resin or the Nylon MXD6contained in the barrier layer 3 is smaller than 20 wt. %, a sufficientbarrier property cannot be provided in some cases.

The barrier layer 3 may preferably have a thickness of about 5 to 60 μm.When the barrier layer 3 has a thickness of below 5 μm, a sufficientbarrier property cannot be provided in some cases. On the other hand,when the thickness of the barrier layer 3 exceeds 60 μm, the nerve orstiffness of the material is too strong at the time of the formation ofthe container, so that not only the container formation becomes somewhatdifficult but also the production cost may undesirably be increased.

The base material layer 4 has a three layer laminate member comprising asupport (or substrate) 5, and resin layers 6 and 7 of an olefin typeresin disposed on both surfaces of the support 5. As the support 5, itis possible to use paper, a biaxially oriented polyester film, biaxiallyoriented polypropylene film, etc. The support 5 is not restricted to onehaving a one layer structure but may also be a laminate. The support 5may preferably have a thickness of about 100 to 600 μm. The polyolefintype resin layers 6 and 7 to be disposed on both sides of the support 5may particularly preferably be polyethylene resin layer. The resinlayers 6 and 7 may preferably have a thickness of about 10 to 60 μm. Thebase material layer 4 may also have a two layer structure comprising thesupport 5 and the polyolefin type resin layer disposed on one sidethereof. In a case wherein base material layer 4 has such a two layerstructure, however, the barrier layer 3 as described above is disposedon one of the surfaces of the base material layer 4 at which the support5 is exposed, and the polyolefin resin layer constitutes an outermostlayer.

The adhesive layer 8b for laminating the barrier layer 3 and the basematerial layer 4 may comprise an adhesive which is similar to thatconstituting the adhesive layer 8a as described above, or may alsocomprise a layer of an isocyanate type adhesive. Such an isocyanate typeadhesive to be used for such a purpose may be a two component curingtype (or two liquid curing type) adhesive which comprises a polyesterpolyurethane type resin or a polyether polyurethane type resin as a basecomponent (or main comonent) and is capable of being cured (or hardened)by use of a curing agent such as tolylene diisocyanate and xylenediisocyanate.

It is preferred to subject the surface of the base material layer 4contactable to the adhesive layer 8b (i.e., polyolefin type resin layer6) to a corona discharging treatment. When such a treatment is used, theadhesion strength between the base material layer 4 and the adhesivelayer 8b may further be improved.

The composite container having a barrier property according to thepresent invention may be prepared, e.g., by cutting or punching thepackaging material as described above so as to provide a predeterminedshape and heat sealing the resultant punched product by hot air heating,flame heating, etc.

FIG. 3 is a schematic sectional view showing a packaging material forforming the composite container having a barrier property according toanother embodiment of the present invention.

In FIG. 3, a packaging material 11 comprises a laminate comprising aninner layer 12 for providing an innermost surface of the container, abarrier layer 13 directly disposed outside the inner layer 12, and abase material layer 14 disposed outside the barrier layer 13 by themedium of an adhesive layer 18.

The above packaging material 11 is characterized in that the inner layer12 thereof comprise a carboxyl group containing polyethylene resin. Thebarrier layer 13, the adhesive layer 18 and the base material layer 14may be the same as the barrier layer 3, the adhesive layer 8a and thebase material layer 4, respectively, constituting the packaging material1 as described above, and therefore the detailed description of theselayers is omitted.

The carboxyl group containing polyethylene resin constituting the innerlayer 12 has an adhesive property to the semi-aromatic polyamide resinor the Nylon MXD6 constituting the barrier layer 13. Accordingly, inthis embodiment, such an inner layer 12 is directly disposed on thebarrier layer 13 without using an adhesive layer to be disposedtherebetween. In this point, the packaging material 11 is different fromthe packaging material 1 as described above.

Specific examples of the above carboxyl group containing polyethyleneresin may include, e.g., an ethylene-methacrylic acid copolymer resin(EMAA), an ethylene-acrylic acid copolymer resin (EAA), an ionomerresin, an ethylene-maleic acid anhydride copolymer resin, an ethylacrylate maleic acid anhydride copolymer resin, etc. The inner layercomprising such a carboxyl group containing polyethylene resin maypreferably have a thickness of about 5 to 100 μm.

FIG. 4 is a schematic sectional view showing a packaging material forforming the composite container having a barrier property according to afurther embodiment of the present invention.

In FIG. 4, a packaging material 21 comprises a laminate comprising aninner layer 22 having a barrier property and a base material layer 23disposed outside the inner layer 22 having a barrier property by themedium of an adhesive layer 27.

The semi-aromatic polyamide resin as described above may preferably becontained in the inner layer 22 having a barrier property in an amountof about 20 to 100 wt. %. When the amount of the semi-aromatic polyamideresin contained in the inner layer 22 is smaller, than 20 wt. %, asufficient barrier property cannot be provide in some cases.

The inner layer 22 having a barrier property may preferably have athickness of about 5 to 60 μm. When the inner layer 22 having a barrierproperty has a thickness of below 5 μm, a sufficient barrier propertycannot be provided or a sufficient sealing strength cannot be providedin some cases. On the other hand, when the thickness of the inner layer22 exceeds 60 μm, the nerve or stiffness of the material is too strongat the time of the formation of the container, so that not only thecontainer formation becomes somewhat difficult but also the productioncost may undesirably be increased.

The adhesive layer 27 for laminating the barrier layer 22 and the basematerial layer 23 may comprise an adhesive which is similar to thatconstituting the adhesive layer 8a of the packaging material 1 asdescribed above. The adhesive layer 27 may preferably have a thicknessof about 1 to 30 μm.

The base material layer 23 comprises a three layer laminate comprising asupport 24 and olefin type resin layers 25 and 26 disposed on both sidesthereof and may have the same structure as that of the base materiallayer 4 as described above. Accordingly, the base material layer 23 mayalso have a two layer structure comprising the support 24 and apolyolefin type resin layer disposed on one side thereof.

It is preferred to subject the surface of the base material layer 23contactable to the adhesive layer (i.e., polyolefin type resin layer 25)to a corona discharging treatment. When such a treatment is used, theadhesion strength between the base material layer 23 and the adhesivelayer 27 may further be improved.

FIG. 5 is a schematic perspective view showing an embodiment of thecomposite container having a barrier property and equipped with apouring member according to the present invention.

FIG. 6 is a schematic sectional view showing a cross section of thecomposite container equipped with a pouring member taken along the lineVI--VI shown in FIG. 5.

As shown in FIG. 5, the composite container 31 having barrier propertyand equipped with a pouring member comprises a main body 32 of thecomposite container and a pouring member 41.

As shown in FIG. 6, the main body 32 of the composite container isformed from a laminate sheet 35 for a composite container whichcomprises at least an inner layer 36 comprising a semi-aromaticpolyamide resin, and, e.g., an intermediate layer 35 and an outermostlayer 38 disposed or laminated thereon.

The semi-aromatic polyamide resin constituting the inner layer 36 may bethe same as that described above. The semi-aromatic polyamide resin maygenerally have a lower crystallinity than that of an ordinary aliphaticpolyamide resin and may show a characteristic of an amorphous resin.Accordingly, such a resin can be subjected to heat sealing (or heatfusing) at a relatively low temperature (e.g., at about 160° C.), and acomposite container may be formed three dimensionally by use of such aheat sealing treatment.

The semi-aromatic polyamide resin may preferably be contained in theinner layer 36 of the main body 32 of the composite container in anamount of about 20 to 100 wt. %. When the amount of the semi-aromaticpolyamide resin contained in the barrier layer 3 is smaller than 20 wt.%, a sufficient barrier property cannot be provided in some cases.

The inner layer 36 may preferably have a thickness of about 5 to 60 μm.When the inner layer 36 has a thickness of below 5 μm, a sufficientbarrier property cannot be provided in some cases. On the other hand,when the thickness of the inner layer 36 exceeds 60 μm, the nerve orstiffness of the material is too strong at the time of the formation ofthe container, so that not only the container formation becomes somewhatdifficult but also the production cost may undesirably be increased.

The intermediate layer 37 to be disposed on the inner layer 36 may, forexample, comprise paper, an aluminum foil, polyolefin type resin, abiaxially oriented polyester film, a biaxially oriented polypropylenefilm, etc., or a laminate of at least two species selected from thesematerials. The intermediate layer 37 may preferably have a thickness ofabout 100 to 600 μm.

The outermost layer 38 may comprise a resin such as polyolefin typeresin which is capable of imparting a water resistance to the container.Specific examples of the polyolefin resin to be used for such a purposemay include low density polyethylene, medium density polyethylene, highdensity polyethylene, an ethylene-vinyl acetate copoplymer, anethylene-acrylic acid copolymer, an ethylene-methyl acrylate copolymer,an ethylene-α-olefin copolymer, polypropylene, etc. Among these, thepolyethylene resins of various types are particularly preferred.

The outermost layer 38 may generally have a thickness of about 3 to 150μm.

At least one adhesive layer (not shown) may generally be disposedbetween the inner layer 36 and the intermediate layer 37, and/or betweenthe intermediate layer 37 and the outermost layer 38. Such an adhesivelayer may comprise an adhesive which is the same as that constitutingthe adhesive layer 8b of the packaging material 1 as described above.The adhesive layer may preferably have a thickness of about 3 to 30 μm.

The main body 32 of the composite container is formed from the laminatesheet 35 for the composite container which has specifically beendescribed hereinabove, e.g., by cutting or punching the laminated sheet35 for the composite container as described above so as to provide apredetermined shape and heat sealing the resultant punched product byhot air heating, flame heating, etc. The main body 32 of the resultantcomposite container may have various shapes or configurations such asgable top type and brick type.

As shown in FIG. 6, a pouring member (or discharging member) 41 isinserted or introduced into an opening formed in the thus prepared mainbody 32 of the composite container from the inner side of the main body32 of the composite container.

As shown in FIG. 6, the pouring member 41 has a flange portion 42 andmay generally comprise an integrally molded member formed from amaterial for forming the pouring member (i.e., a pouring member formingmaterial). The pouring member 41 may be constituted by use of a pouringmember forming material comprising the adhesive polyolefin type resin orthe semi-aromatic polyamide resin as described above.

The amount of the adhesive polyolefin type resin contained in thepouring member forming material as described above may generally be 40to 100 wt. %, more preferably 60 to 100 wt. %. When the pouring memberforming material contains another component in addition to the adhesivepolyolefin type resin, specific examples of such a component may includepolyethylene, an ethylene-α-olefin copolymer, an ethylene-methylmethacrylate copolymer, etc.

On the other hand, the amount of the semi-aromatic polyamide resincontained in the pouring member forming material as described above maygenerally be 20 to 100 wt. %, more preferably 60 to 300 wt. %. When thepouring member forming material contains another component in additionto the semi-aromatic polyamide resin, specific examples of such acomponent may include Nylon 6, Nylon 66, Nylon 12, polyethyleneterephthalate (PET), etc.

The above pouring member forming material does not necessarilyconstitute the entirety of the pouring member 41, but it is possiblethat at least a portion of the pouring member 41 which is to be bondedto the main body 32 of the composite container, such as the flangeportion 42, comprises the pouring member forming material as describedabove. The pouring member 41 may also be equipped with a pulling ring45. In FIG. 6, the reference numeral 46 denotes a thin circular groovewhich facilities the breakage of the flange portion 42, and thereference numeral 49 denotes a cap for the pouring opening (or dischargeoutlet) which is mounted to the pouring opening of the pouring member41.

The inner layer 36 of the main body 32 of the composite container andthe flange portion 42 of the pouring member 41 are fused to each otherunder heating so that the flange portion 42 of the pouring member 41 isfixed to the inner peripheral surface 36 of the main body 32 of thecomposite container.

FIG. 7 is a schematic perspective view for illustrating an embodiment ofthe composite container having a barrier property and equipped with apouring member according to the present invention.

FIG. 8 is a schematic sectional view showing a cross section of thecomposite container equipped with the pouring member taken along theline VIII--VIII shown in FIG. 7.

As shown in FIG. 7, the composite container 61 having a barrier propertyand equipped with a pouring member comprises a main body 62 of thecomposite container and a pouring member 71.

As shown in FIG. 8, the main body 62 of the composite container isformed from a laminate sheet 65 for a composite container whichcomprises at least an inner layer 66 comprising the semi-aromaticpolyamide resin as described above, and, e.g., an intermediate layer 67and an outermost layer 68 disposed or laminated thereon.

The inner layer 66, the intermediate layer 67 and the outermost layer 68respectively correspond to the inner layer 36, the intermediate layer 32and the outermost layer 38 of the main body 32 of the compositecontainer as described above, and therefore the detailed description ofthese layers is omitted.

The pouring member 71 may for example comprise an integrally moldedmember formed from a polyolefin resin such as polyethylenes of varioustypes, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acidcopolymer, an ethylene-methyl acrylate copolymer, an ethylene-α-olefincopolymer and, polypropylene. As shown in FIG. 8, the pouring member 71has a flange portion 72. The pouring member 71 may also be equipped witha pulling ring 75. In FIG. 8, the reference numeral 76 denotes a thincircular groove which facilitates the breakage of the flange portion 72,and the reference numeral 79 denotes a cap for the pouring opening (ordischarge outlet) which is mounted to the pouring opening of the pouringmember 71.

As shown in FIG. 8, a laminating material 81 is disposed between theflange portion 72 of the pouring member 71 and the inner peripheralsurface layer 66 of the main body 62 of the composite container.

The laminating material 81 comprises a laminate comprising at least asemi-aromatic polyamide resin layer 82, and, e.g., a base material layer83 and a polyolefin type resin layer 84.

The laminating material 81 is disposed between the flange portion 72 ofthe pouring member 71 and the inner layer 66 of the main body 62 of thecomposite container so that the above semi-aromatic polyamide resinlayer 82 is disposed opposite to the inner layer 66 of the main body 62of the composite container.

The semi-aromatic polyamide resin layer 82 comprises the semi-aromaticpolyamide resin as described above, and may generally have a thicknessof about 3 to 60 μm.

The base material layer 83 laminated on the semi-aromatic polyamideresin layer 82 may for example comprise a stretched (or oriented)polyethylene terephthalate (PET) resin, an aluminum foil, a stretchedpolypropylene resin, a stretched nylon resin, etc., and may generallyhave a thickness of about 7 to 50 μm.

The polyolefin type resin layer 84 laminated on the above base materiallayer 83 may for example comprise a polyolefin type resin such aspolyethylenes of various types, and may particularly preferably comprisea resin which is the same as the polyolefin type resin constituting theoutermost layer 68 of the laminate sheet 65 for forming the above mainbody 62 of the composite container. When the polyolefin type resinconstituting the polyolefin type resin layer 84 comprises the same resinas the polyolefin type resin constituting the outermost layer 68 of themain body 62 of the composite container, the adhesion property betweenthe flange portion 72 of the pouring member 71 and the laminatingmaterial 81 may be improved.

The laminating material 81 having the above layer structure maygenerally have a thickness of, e.g., about 20 to 250 μm.

The laminating material 81 is not necessarily required to have the threelayer structure as described above, but may also have a two layerstructure, e.g., comprising the semi-aromatic polyamide resin layer 82and the polyolefin type resin layer 84. However, when the laminatingmaterial 81 has such a two layer structure, the laminating material 81is disposed between the pouring member 71 and the main body 62 of thecomposite container so that the above semi-aromatic polyamide resinlayer 82 is disposed opposite to the inner layer 66 of the main body 62of the composite container.

The inner layer 66 of the main body 62 of the composite container andthe flange portion 72 of the pouring member 71 are fused to each otherby the medium of the laminating material 81 under heating so that theflange portion 72 of the pouring member 71 is fixed to the inner surface66 side of the main body 62 of the composite container.

Hereinbelow, the present invention will be described in further detailwith reference to specific Experiment Examples.

EXPERIMENTAL EXAMPLE 1

(Sample 1)

First, an acid resistant paper having a basis weight of 400 g/m² wasused as a support, and a low density polyethylene resin (Mirason 16sp,mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) as a polyolefin type resin wasextrusion laminated on both surface sides of the acid resistant paper soas to respectively form 20 μm thick resin layers, whereby a basematerial layer having a three layer structure was prepared.

One surface side of the resultant base material layer is subjected to acorona discharge treatment, and an isocyanate type adhesive (TakelacA310 and Takenate A 3, mfd. by Takeda Yakuhin Kogyo K.K.) was appliedonto the thus treated surface to form an adhesive layer. Thereafter, onthe thus formed adhesive layer, a 10 μm thick barrier layer comprising apolyamide resin (Nylon MXD6 grade 6007, mfd. by Mitsubishi Gas KagakuK.K.), a 10 μm thick adhesive layer comprising an adhesive polyolefinresin (Addmer AT 499, mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.), and a 30μm thick inner layer comprising a low density polyethylene resin(Mirason 16sp, mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) weresequentially laminated in this order by co-extrusion laminating, therebyto provide a packaging material (Sample 1) as shown in FIG. 1.

(Sample 2)

An acid resistant paper having a basis weight of 400 g/m² was used as asupport, and a low density polyethylene resin (Mirason 16sp, mfd. byMitsui Sekiyu Kagaku Kogyo K.K.) as a polyolefin type resin wasextrusion laminated on one surface side of the acid resistant paper soas to form 20 μm thick resin layer, whereby a base material layer havinga two layer structure was prepared.

One surface side of the resultant base material layer at which the papersurface was exposed, a low density polyethylene resin (Mirason 16sp,mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated, whilea co-extrusion film having the following structure was fused theretounder heating to effect laminating, thereby to provide a packagingmaterial (Sample 2). Such a laminating method is ordinarily referred toas poly sandwiching

Structure of co-extrusion film (thickness: 40 μm) low densitypolyethylene (thickness: 10 μm)/adhesive polyethylene (thickness: 5μm)/polyamide (nylon MXD6) (thickness: 10 μm)/adhesive polyethylene(thickness: 5 μm)/low density polyethylene (thickness: 10 μm)

In the above film, the low density polyethylene was the above Mirason16sp (mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.), the adhesivepolyethylene was Addmer AT 499 (mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.)and the polyamide resin (Nylon MXD6) was Nylon MXD6 grade 6007 (mfd. byMitsubishi Gas Kagaku K.K.).

(Comparative Sample 1)

A packaging material (Comparative Sample 1) was prepared in the samemanner as in the preparation of the above Sample 1 except that apolyamide resin (Nylon 6, mfd. by Mitsubishi Kasei K.K.) was used as thematerial constituting the barrier layer.

(Comparative Sample 2)

A packaging material (Comparative Sample 2) was prepared in the samemanner as in the preparation of the above Sample 1 except that anethylene-vinyl alcohol copolymer (Eval E, mfd. by Kuraray K.K.) was usedas the material constituting the barrier layer.

Then, each of the packaging materials as prepared above was punched intoa predetermined size and was formed into a container sample with abottom by using a predetermined container formation process. Withrespect to each of the respective container samples with a bottom, thebarrier property and the container strength thereof were evaluated underthe following measurement conditions. The thus obtained results areshown in Table 1 appearing hereinafter.

(Measurement conditions)

Barrier property

The container with a bottom had a dimensions of 70 mm×70 nm and a heightof 180 mm, and was generally referred to as Gable top type carton forcontaining therein a liquid food or drink such as milk and orange juice.

With respect to the barrier property, the oxygen permeability per onecontainer was measured under normal temperature and normal pressure byuse of a measurement device (trade name: Oxytran, mfd. by Modern ControlCo.).

Strength of container

The container with a bottom was dropped from a position having a heightof 90 cm so that the lower surface disposed below, and the resultantstate of liquid leakage was evaluated.

                  TABLE 1                                                         ______________________________________                                                                  Container strength                                          Barrier property  Number of containers                                        (cc/container ·                                                                        causing liquid leakage                              Sample  24 hr · atm)                                                                           Number of tested containers                         ______________________________________                                        Sample 1                                                                              50          0.05                                                      Sample 2                                                                              50          0.02                                                      Comparative                                                                           400         0.02                                                      Sample 1                                                                      Comparative                                                                           80          0.5                                                       Sample 2                                                                      ______________________________________                                    

As shown in the above Table 1, the containers formed from Samples 1 and2 had both of a good barrier property and a high strength. On the otherhand, the container formed from Comparative Sample 1 had a sufficientstrength but was poor in the barrier property. Further, the containerformed from Comparative Sample 2 had a good barrier property but onlyhad an insufficient strength.

EXPERIMENT EXAMPLE 2

(Sample 1)

First, a base material layer having a three layer structure was preparedin the same manner as in the preparation of Sample 1 in ExperimentExample 1.

One surface side of the resultant base material layer way subjected to acorona discharge treatment, and an isocyanate type adhesive (TakelacA310 and Takenate A. 3, mfd. by Takeda Yakuhin Kogyo K.K.) was appliedonto the thus treated surface to form an adhesive layer. Thereafter, onthe thus formed adhesive layer, a 10 μm thick barrier layer comprising asemi-aromatic polyamide resin (Novamid X21, mfd. by Mitsubishi KaseiK.K.) and a 30 μm thick inner layer comprising a carboxyl groupcontaining polyethylene resin (New Kurel 0908C, mfd. by Mitsui Du PontPolychemical K.K.) were sequentially laminated in this order byco-extrusion laminating, thereby to provide a packaging material(Sample 1) as shown in FIG. 3.

(Sample 2)

First, a base material layer having a two layer structure was preparedin the same manner as in the preparation of Sample 2 in ExperimentExample 1.

One surface side of the resultant base material layer at which the papersurface was exposed, a low density polyethylene resin (Mirason 16sp,mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated, whilea co-extrusion film having the following structure was fused theretounder heating to effect laminating, thereby to provide a packagingmaterial (Sample 2).

Structure of co-extrusion film (thickness: 35 μm) low densitypolyethylene (thickness: 10 μm)/adhesive polyethylene (thickness: 5μm)/Nylon MXD6 (thickness: 10 μm)/carboxyl group containing polyethylene(thickness: 10 μm).

In the above film, the lowdensity polyethylene was the above Mirason16sp (mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.), the adhesivepolyethylene was Addmer AT 499 (mfd. by Mitsui Sekiyu Kagaku KogyoK.K.), the Nylon MXD6 was Nylon MXD6 grade 6007 (mfd. by Mitsubishi GasKagaku K.K.), and the carboxyl group containing polyethylene resin wasNew Kurel 0908C (mfd. by Mitsui Du Pont Polychemical K.K.).

(Comparative Sample 1)

A packaging material (Comparative Sample 1) was prepared in the samemanner as in the preparation of the above Sample 1 except that apolyamide resin (Nylon 6) (Novamid 1030, mfd. by Mitsubishi Kasei K.K.)was used as the material constituting the barrier layer.

(Comparative Sample 2)

A packaging material (Comparative Sample 2) was prepared in the samemanner as in the preparation of the above Sample 1 except that anethylene-vinyl alcohol copolymer (Eval E, mfd. by Kuraray K.K.) was usedas the material constituting the barrier layer.

Then, each of the packaging materials as prepared above was punched intoa predetermined size and was formed into a container sample with abottom by using a predetermined container formation process. Withrespect to each of the respective container samples with a bottom, thebarrier property and the container strength thereof were evaluated underthe measurement conditions which were the same as those used inExperiment Example 1. The thus obtained results are shown in Table 2appearing hereinafter.

                  TABLE 2                                                         ______________________________________                                                                  Container strength                                          Barrier property  Number of containers                                        (cc/container ·                                                                        causing liquid leakage                              Sample  24 hr · atm)                                                                           Number of tested containers                         ______________________________________                                        Sample 1                                                                              80          0.04                                                      Sample 2                                                                              80          0.04                                                      Comparative                                                                           400         0.02                                                      Sample 1                                                                      Comparative                                                                           80          0.5                                                       Sample 2                                                                      ______________________________________                                    

As shown in the above Table 2, the containers formed from Samples 1 and2 had both of a good barrier property and a high strength. On the otherhand, the container formed from Comparative Sample 1 had a sufficientstrength but was poor in the barrier property. Further, the containerformed from Comparative Sample 2 had a good barrier property but onlyhad an insufficient strength.

EXPERIMENT EXAMPLE 3

(Sample 1)

First, a base material layer having a three layer structure was preparedin the same-manner as in the preparation of Sample 1 in ExperimentExample 1.

Then, by use of the resultant base material layer, a packaging material(Sample 1) was Prepared in the same manner as in the preparation of theabove Sample 1 in Experiment Example 1 except that a semi-aromaticpolyamide resin (Novamid X21, mfd. by Mitsubishi Kasei K.K.) was used asthe material constituting the barrier layer.

(Sample 2)

A packaging material (Sample 2) was prepared in the same manner as inthe preparation of the above Sample 2 in the Experiment Example 1 exceptthat a co-extrusion film having the following structure was used insteadof that used in Sample 2 of Experiment Example 1.

Structure of co-extrusion film (thickness: 40 μm) low densitypolyethylene (thickness: 10 μm)/adhesive Polyethylene (thickness: 5μm)/semi-aromatic polyamide resin (thickness: 10 μm)/adhesivepolyethylene (thickness: 5 μm)/low density Polyethylene (thickness: 10μm)

In the above film, the low density polyethylene was the above Mirason16sp (mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.), the adhesivePolyethylene was Addmer AT 499 (mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.)and the semi-aromatic polyamide resin was Novamid X21 (mfd. byMitsubishi Kasei Kogyo K.K.).

Then, each of the packaging materials as prepared above Samples 1 and 2and Comparative Samples 1 and 2 prepared in Experiment Example 1 waspunched into a predetermined size and was formed into a container samplewith a bottom by using a predetermined container formation process. Withrespect to each of the respective container samples with a bottom, thebarrier property and the container strength thereof were evaluated underthe measurement conditions which were the same as those used inExperiment Example 1. The thus obtained results are shown in Table 3appearing hereinafter.

                  TABLE 3                                                         ______________________________________                                                                  Container strength                                          Barrier property  Number of containers                                        (cc/container ·                                                                        causing liquid leakage                              Sample  24 hr · atm)                                                                           Number of tested containers                         ______________________________________                                        Sample 1                                                                              100         0.02                                                      Sample 2                                                                              100         0.02                                                      Comparative                                                                           400         0.02                                                      Sample 1                                                                      Comparative                                                                           80          0.5                                                       Sample 2                                                                      ______________________________________                                    

As shown in the above Table 3, the containers formed from Samples 1 and2 had both of a good barrier property and a high strength. On the otherhand, the container formed from Comparative Sample 1 of ExperimentExample 1 had a sufficient strength but was poor in the barrierproperty. Further, the container formed from Comparative Sample 2 ofExperiment Example 1 had a good barrier property but only had aninsufficient strength.

EXPERIMENT EXAMPLE 4

(Sample 1)

First, a base material layer having a three layer structure was preparedin the same manner as in the preparation of Sample 1 in ExperimentExample 1.

One surface side of the resultant base material layer is subjected to acorona discharge treatment, and on the thus treated surface, a 10 μmthick adhesive layer comprising an adhesive polyolefin resin (Addmer AT499, mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.), and a 10 μm thick innerlayer having a barrier property and comprising a semi-aromatic polyamideresin (Novamid X21, mfd. by Mitsubishi Kasei K.K.), were sequentiallylaminated in this order by co-extrusion laminating, thereby to provide apackaging material (Sample 1) as shown in FIG. 4.

(Sample 2)

First, a base material layer having a two layer structure was preparedin the same manner as in the preparation of Sample 2 in ExperimentExample 1.

One surface side of the resultant base material layer at which the papersurface was exposed, a low density polyethylene resin (Mirason 16sp,mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated, whilea co-extrusion film having the following structure was fused theretounder heating to effect laminating, thereby to provide a packagingmaterial (Sample 2).

Structure of co-extrusion film (thickness: 25 μm) low densitypolyethylene (thickness: 10 μm)/adhesive. polyethylene (thickness: 5μm)/semi-aromatic polyamide resin (thickness: 10 μm).

In the above film, the low density polyethylene was the above Mirason16sp (mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.), the adhesivepolyethylene was Addmer AT 499 (mfd. by Mitsui Sekiyu Kagaku KogyoK.K.), and the semi-aromatic polyamide resin was Novamid X21(mfd. byMitsubishi Kasei Kogyo K.K.).

(Comparative Sample 1)

A packaging material (Comparative Sample 1) was prepared in the samemanner as in the preparation of the above Sample 1 except that apolyethylene resin (PETG 6763, mfd. by Eastman Kodak Co.) was used asthe material constituting the inner layer having a barrier property.

(Comparative Sample 2)

A packaging material (Comparative Sample 2) was prepared in the samemanner as in the preparation of the above Sample 1 except that anethylene-vinyl alcohol copolymer (Eval E, mfd. by Kuraray K.K.) was usedas the material constituting the inner layer having a barrier property.

Then, each of the packaging materials as prepared above was punched intoa predetermined size and was formed into a container sample with abottom by using a predetermined container formation process. Withrespect to each of the respective container samples with a bottom, thebarrier property and the container strength thereof ware evaluated underthe measurement conditions which were the same as those used inExperiment Example 1. The thus obtained results are shown in Table 4appearing hereinafter.

                  TABLE 4                                                         ______________________________________                                                                  Container strength                                          Barrier property  Number of containers                                        (cc/container ·                                                                        causing liquid leakage                              Sample  24 hr · atm)                                                                           Number of tested containers                         ______________________________________                                        Sample 1                                                                              80          0.04                                                      Sample 2                                                                              80          0.04                                                      Comparative                                                                           500         0.8                                                       Sample 1                                                                      Comparative                                                                           100         0.5                                                       Sample 2                                                                      ______________________________________                                    

As shown in the above Table 4, the containers formed from Samples 1 and2 not only had both of a good barrier property and a high strength. Onthe other hand, the container formed from Comparative Samples 1 and 2had an insufficient strength and were poor in the barrier property.

Experiment Example 5

(Sample 1)

An acid resistant paper having a basis weight of 400 g/m² was used as anintermediate layer, and a low density polyethylene resin (Mirason 16 sp,mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated on onesurface side of the acid resistant paper, and a semi-aromatic polyamideresin (Novamid X 21, mfd. by Mitsubishi Kasei Kogyo K.K.) was extrusionlaminated on the other surface side thereof to form a 20 μm thickoutermost layer and a 30 μm thick inner layer, respectively, whereby alaminate sheet having a three layer structure was prepared.

The thus prepared laminate sheet for a composite container was punchedinto a blank having a predetermined shape corresponding to a gable toptype container. Then, a pouring member comprising an integrally moldedmember comprising an adhesive polyolefin resin (Addmer AT 469C, mfd. byMitsui Sekiyu Kagaku Kogyo K.K.) was inserted into an opening portionwhich had been formed in the above blank in advance, and thereafter theflange portion of the pouring member was fused to the inner peripheralsurface layer of the above laminate sheet while being heated.

A composite container (Sample 1) having a barrier property and equippedwith the pouring member was prepared according to an ordinary process byuse of the blank to which the pouring member had been fixed in the abovemanner.

(Sample 2)

A composite container (Sample 2) having a barrier property and equippedwith a pouring member was prepared in the same manner as in thepreparation of the above Sample 1 except that a pouring membercomprising an integrally molded member comprising a semi-aromaticpolyamide resin (Novamid X21, mfd. by Mitsubishi Kasei Kogyo K.K.) wasused instead of the pouring member used in the preparation of Sample 1.

With respect to the thus prepared Samples 1 and 2, the adhesion propertybetween the pouring member and the main body of the container wasevaluated in the following manner. Thus, when the pouring member and themain body of the container were intended to be separate from each otherby using hands, the separation or peeling did not occur between thebonded surface (or bond interface) between the above two members butthere occurred a separation (i.e., a so-called paper peeling ) betweenthe acid resistant paper layers constituting the main body of thecomposite container. As a result, it was confirmed that the adhesionproperty between the pouring member and the composite container wasgood.

(Comparative Sample 1)

A composite container (Comparative Sample 1) equipped with a pouringmember was prepared in the same manner as in the preparation of theabove Sample 1 except that a pouring member comprising an integrallymolded member comprising a low density polyethylene resin (Mirason 16sp, mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) was used instead of thepouring member used in the preparation of Sample 1.

With respect to the thus prepared Comparative Sample 1, the adhesionproperty between the pouring member and the main body of the containerwas evaluated in the same manner as in the case of the above Sample 1.As a result, it was confirmed that the pouring member and the main bodyof the composite container were easily separated from each other at thebond interface therebetween.

(Comparative Sample 2)

A composite container (Comparative Sample 2) equipped with a pouringmember was prepared in the same manner as in the preparation of theabove Sample 2 except that a pouring member comprising an integrallymolded member comprising a low density polyethylene resin (Mirason 16sp, mfd. by Mitsui Sekiyu Kagaku Kogyo K.K.) was used instead of thepouring member used in the preparation of Sample 2.

With respect to the thus prepared Comparative Sample 2, the flavorbarrier property and the adhesion property between the pouring memberand the main body of the container were evaluated. As a result, it wasconfirmed that the Comparative Sample 2 had a good flavor barrierproperty but the pouring member and the main body of the compositecontainer were easily separated from each other at the bond interfacetherebetween.

(Comparative Sample 3)

An acid resistant paper having a basis weight of 400 g/m² was used as asupport, and a low density polyethylene resin (Mirason 16sp, mfd. byMitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated on both surfacesides of the acid resistant paper so as to respectively form 20 μm thickresin layers, whereby a laminate sheet for a composite container layerhaving a three layer structure was prepared.

A composite container (Comparative Sample 3) equipped with a pouringmember was prepared in the same manner as in the preparation of theabove Sample 1 except that the thus prepared laminate sheet for acomposite container was used instead of the laminate sheet used in thepreparation of Sample 1.

With respect to the thus prepared Comparative Sample 3, the adhesionproperty between the pouring member and the main body of the containerwas evaluated in the same manner as in the case of the above Sample 1.As a result, it was confirmed that the pouring member and the main bodyof the composite container were easily separated from each other at thebond interface therebetween.

(Comparative Sample 4)

An acid resistant paper having a basis weight of 400 g/m² was used as asupport, and a low density polyethylene resin (Mirason 16sp, mfd byMitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated on both surfacesides of the acid resistant paper so as to respectively form 20 μm thickresin layers, whereby a laminate sheet for a composite container layerhaving a three layer structure was prepared.

A composite container (Comparative Sample 4) equipped with a pouringmember was prepared in the same manner as in the preparation of theabove Sample 2 except that the thus prepared laminate sheet for acomposite container was used instead of the laminate sheet used in thepreparation of Sample 2.

With respect to the thus prepared Comparative Sample 4, the flavorbarrier property and the adhesion property between the pouring memberand the main body of the container were evaluated. As a result, it wasconfirmed that the Comparative Sample 4 was poor in the flavor barrierproperty and the pouring member and the main body of the compositecontainer were easily separated from each other.

EXPERIMENT EXAMPLE 6

(Sample 1)

First, a laminate sheet for a composite container having a three layerstructure was prepared in the same manner as in the preparation ofSample 1 in Experiment Example 5.

The thus prepared laminate sheet for a composite container was punchedinto a blank having a predetermined shape corresponding to a gable toptype container. Then, a pouring member was inserted into an openingportion which had been formed in the above blank in advance, from theinner side layer of the composite container by the medium of alaminating material having the following layer structure, and thereafterthe flange portion of the pouring member, the inner surface layer of theabove laminate sheet and the laminating material were fused to eachother while being heated. At this time, the laminating material wasdisposed between the inner surface layer and the flange portion of thepouring member so that the semi-aromatic polyamide resin layer of thelaminating material was disposed opposite to the inner layer of thelaminate sheet.

Structure of laminating material

semi-aromatic polyamide resin (thickness: 30 μm)/base material layer(thickness: 12 μm)/polyolefin type resin layer (thickness: 40 μm).

In the above laminating material, the semi-aromatic polyamide resin wasNovamid X 21 (mfd. by Mitsubishi Kasei Kogyo K.K.), the polyolefin typeresin was a low density polyethylene resin (Mirason 16sp, mfd. by MitsuiSekiyu Kagaku Kogyo K.K.). Further, the base material layer was formedby use of a biaxially oriented polyester resin.

In addition, the above pouring member was one comprising an integrallymolded member comprising a polyolefin type resin.

A composite container (Sample 1) having a barrier property and equippedwith the pouring member was prepared according to an ordinary process byuse of the blank to which the pouring member had been fixed in the abovemanner.

With respect to the thus prepared Sample 1, the adhesion propertybetween the pouring member and the main body of the composite containerwas evaluated in the same manner as in Experiment Example 5. As aresult, it was confirmed that the adhesion property between the pouringmember and the main body of the composite container was good.

(Sample 2)

A composite container (Sample 2) having a barrier property and equippedwith a pouring member was prepared in the same manner as in thepreparation of the above Sample 1 except that a laminating materialhaving the following layer structure was used instead of that used inSample 1.

Structure of laminating material

semi-aromatic polyamide resin (thickness: 50 μm)/polyolefin type resinlayer (thickness: 50 μm)

In the above laminating material, the semi-aromatic polyamide resin wasNovamid X 21 (mfd. by Mitsubishi Kasei Kogyo K.K.), the polyolefin typeresin was a low density polyethylene resin (Mirason 16sp, mfd. by MitsuiSekiyu Kagaku Kogyo K.K.).

With respect to the thus prepared Sample 2, the adhesion propertybetween the pouring member and the main body of the composite containerwas evaluated in the same manner as in the case of Sample 1. As aresult, it was confirmed that the adhesion property between the pouringmember and the main body of the composite container was good.

(Comparative Sample 1)

A composite container (Comparative Sample 1) equipped with a pouringmember was prepared in the same manner as in the preparation of theabove Sample 1 except that a laminating material was not used.

With respect to the thus prepared Comparative Sample 1, the adhesionproperty between the pouring member and the main body of the compositecontainer was evaluated in the same manner as in the case of Sample 1.As a result, it was confirmed that the pouring member and the main bodyof the composite container were easily separated from each other at thebond interface therebetween.

(Comparative Sample 2)

An acid resistant paper having a basis weight of 400 g/m² was used as asupport, and a low density polyethylene resin (Mirason 16 sp, mfd. byMitsui Sekiyu Kagaku Kogyo K.K.) was extrusion laminated on both surfacesides of the acid resistant paper so as to respectively form 20 μm thickresin layers, whereby a laminate sheet for a composite container havinga three layer structure was prepared.

The thus prepared laminate sheet for a composite container was punchedinto a blank having a predetermined shape corresponding to a gable toptype container. Then, a pouring member comprising an integrally moldedmember comprising an adhesive polyolefin resin was inserted into anopening portion which had been formed in the above blank in advance, andthereafter the flange portion of the pouring member was fused to theabove blank while being heated.

A composite container (Comparative Sample 2) equipped with the pouringmember was prepared according to an ordinary process by use of the blankto which the pouring member had been fixed in the above manner.

With respect to the thus prepared Comparative Sample 2, the flavorbarrier property and the adhesion property between the pouring memberand the main body of the container were evaluated. As a result, it wasconfirmed that the pouring member and the main body of the compositecontainer were not easily separated from each other, but the ComparativeSample 2 was poor in the flavor barrier property.

What is claimed is:
 1. A composite container having a barrier property and comprising a packaging material which comprises:an inner surface layer comprising a polyolefin resin, a barrier layer, and a base material layer wherein at least an outermost layer thereof comprises an olefin resin, wherein the barrier layer contains a polyamide resin of not less than 20 weight % which is a copolymer comprising an aromatic polyamide forming component of not less than 60 weight % and further containing a positive amount of an aliphatic polyamide forming component, the aromatic polyamide forming component comprising an aliphatic diamine and at least one of isophthalic acid and terephthalic acid, the aliphatic polyamide forming component comprising a lactam or an aliphatic diamine and an aliphatic dicarboxylic acid, said barrier layer having a thickness effective for being provided with a sufficient oxygen barrier property.
 2. A composite container having a barrier property according to claim 1, wherein the inner surface layer comprises a carboxyl group containing polyethylene resin.
 3. A composite container having a barrier property according to claim 1, wherein the base material layer has a three layer structure comprising a polyolefin resin layer, a support and a polyolefin resin layer.
 4. A composite container having a barrier property according to claim 1, wherein the base material layer has a two layer structure comprising a polyolefin resin layer and a support.
 5. A composite container having a barrier property according to claim 1, further comprising an adhesive layer between the inner surface layer and the barrier layer.
 6. A composite container having a barrier property according to claim 1, further comprising an adhesive layer between the barrier layer and the base material layer.
 7. A composite container having a barrier property according to claim 6, further comprising an adhesive layer between the inner surface layer and the barrier layer.
 8. A composite container according to claim 1 wherein said barrier layer has a thickness of 5 to 60 μm.
 9. A composite container having a barrier property and comprising a packaging material which comprises:an inner surface layer having a barrier property, and a base material layer wherein at least an outermost layer thereof comprises an olefin resin, wherein the inner surface layer having the barrier property contains a polyamide resin of not less than 20 weight % which is a copolymer comprising an aromatic polyamide forming component of not less than 60 weight % and further containing a positive amount of an aliphatic polyamide forming component, the aromatic polyamide forming component comprising a lactam or an aliphatic diamine and an aliphatic dicarboxylic acid, said barrier layer having a thickness effective for being provided with a sufficient oxygen barrier property.
 10. A composite container having a barrier property according to claim 9, wherein the base material layer has a three layer structure comprising a polyolefin resin layer, a support and a polyolefin resin layer.
 11. A composite container having a barrier property according to claim 9, wherein the base material layer has a two layer structure comprising a polyolefin resin layer and a support.
 12. A composite container having a barrier property according to claim 9, further comprising an adhesive layer between the inner surface layer having a barrier property and the base material layer.
 13. A composite container according to claim 9, wherein said inner surface layer has a thickness of 5 to 60 μm.
 14. A composite container having a barrier property and comprising a packaging material which comprises:an inner surface layer having a barrier property, and a base material layer wherein at least an outermost layer thereof comprises an olefin resin, wherein the inner surface layer having the barrier property contains substantially only a polyamide resin polyamide resin being a copolymer comprising an aromatic polyamide forming component of not less than 60 weight % and further containing a positive amount of an aliphatic polyamide forming component of not more than 40 weight %, the aromatic polyamide forming component comprising an aliphatic diamine and at least one of isophthalic acid and terephthalic acid, the aliphatic polyamide forming component comprising a lactam or an aliphatic diamine and an aliphatic dicarboxylic acid, said barrier layer having a thickness effective for being provided with a sufficient oxygen barrier property.
 15. A composite container having a barrier property according to claim 14, wherein the base material layer has a three layer structure comprising a polyolefin resin layer, a support and a polyolefin resin layer.
 16. A composite container having a barrier property according to claim 14, wherein the base material layer has a two layer structure comprising a polyolefin resin layer and a support.
 17. A composite container having a barrier property according to claim 14, further comprising an adhesive layer between the inner surface layer having a barrier property and the base material layer.
 18. A composite container according to claim 14, wherein said inner surface layer has a thickness of 5 to 60 μm. 